BANGKOK (Reuters) - Members of Thailand's
Senate trying to devise a "road map" out of a long political crisis are
expected on Friday to propose the appointment of an interim prime
minister, a move which would infuriate supporters of a beleaguered
caretaker government.

The caretaker administration loyal to Yingluck Shinawatra, who was
ousted as prime minister by a court last week, wants to organize a
fresh election it would likely win.

But anti-government protesters backed by the royalist establishment
want a "neutral" interim prime minister to replace the government
and implement electoral changes end the influence of Yingluck's
brother, ousted former premier Thaksin Shinawatra.

The Senate is the only legislative assembly still functioning after
six months of anti-government protests and a disrupted February
election that was later declared void.

A Senate working group has been consulting public and private sector
representatives on a way out of the deadlock and it is likely to
recommend an interim prime minister with "full powers" to replace
the caretaker government with limited ones.

"Most groups we talked to agree that an interim prime minister to
temporarily solve the country's problems is a solution," working
group member Jate Siratharanont told Reuters.

The working group is expected to make its recommendation to an
informal gathering of the Senate later on Friday, he said.

Just how a formal decision to appoint an interim prime minister
would be made and implemented is not clear. Critics say it would be
unconstitutional.

The caretaker government says it still has a mandate to organize a
new election. It had tentatively set a July 20 date, but the
Election Commission says it needs more time.

The government's "red shirt" supporters, thousands of whom are
rallying on the outskirts of Bangkok while they cling to hopes for
an election that would return Thaksin's loyalists to power, have
warned of violence if the government is ousted.

The turmoil that began with anti-government protests in November is
the latest phase in nearly a decade of animosity between the
royalist establishment and Thaksin, a former telecommunications
billionaire who won huge support among the rural and urban poor.

He was dogged by accusations of corruption, heavy-handed rule and
even disrespect towards the monarchy and was deposed by the military
in a 2006 coup. He has lived in self-exile since 2008 but exerts
huge influence from abroad.

UNCERTAINTY

More than half the members of the 150-seat Senate are elected, with
the rest appointed. Most elected members side with the government
and have said they do not agree with an interim premier, raising
doubts over whether the Senate can even reach a conclusive decision.

Fuelling uncertainty, acting Prime Minister Niwatthamrong
Boonsongphaisan is out of Bangkok, inspecting damage in the northern
city of Chiang Rai after an earthquake last week.

Niwatthamrong, appointed after Yingluck's ouster, was on Thursday
forced to flee from a meeting with election officials when
anti-government protesters broke into the air force compound where
the talks were being held.

That came hours after a gun and grenade attack on anti-government
protests in Bangkok's historic area in which three people were
killed, the deadliest outbreak of violence since February.

The attack prompted the army chief to warn that his men "may need to
come out in full force" if violence escalates. Twenty-eight people
have been killed since November.

The anti-government protesters accuse Thaksin of using his vast
wealth to woo poor voters in rural areas, ensuring victory for his
party in every election since 2001.

"If we go to the polls who will guarantee that wicked people won't
be voted in again?" anti-government protest leader Suthep Thaugsuban
told election commissioners in a meeting on Thursday.

"This is why we must reform the electoral system first."

Suthep has threatened to set up a "people's assembly" if the Senate
does not install an interim premier.

(Additional reporting by Aukkarapon Niyomyat; Editing by Robert
Birsel and Alex Richardson)